* NPR’s Diane Rehm Showdevoted an hour to Sen. Bernie Sanders, the independent socialist from Vermont, talking about his new book The Speech. But it looks like Diane has not interviewed Sen. Rand Paul, the constitutional conservative from Kentucky, about his new book The Tea Party Goes to Washington, even though it’s selling better than Sanders’s book. It’s pretty clear to book publicists that it’s much easier to get a liberal author on the Diane Rehm Show than a conservative or libertarian author.

* Meanwhile, this week PBS is featuring the latest in its program Journey to Planet Earth, this episode featuring “environmental visionary Lester Brown,” the long-time president of the Worldwatch Institute. The episode, “Plan B: Mobilizing To Save Civilization,” “delivers a clear and unflinching message – either confront the realities of climate change or suffer the consequences of lost civilizations and failed political states.” Matt Damon hosts. But Lester Brown’s decades-long predictions about environmental disasters have been wrong more often than the 5.9 million NCAA brackets filled out on ESPN. See this review from 1999 or this one from 2000 or this one from 2009. Meanwhile, a PBS documentary featuring the ideas of Julian Simon, who challenged doomsday orthodoxy and notably got things right? Don’t bet on it.

* Check out the Forum Network, “a PBS and NPR public media service in collaboration with public stations and community partners across the United States [intended] to bring a diverse range of perspectives on both local and global issues to audiences around the world” through an online library of “thousands of lectures by some of the world’s foremost scholars, authors, artists, scientists, policy makers, and community leaders, available to citizens of the world for free.” If the tilt of the videos isn’t obvious, just click on any letter under Speakers and see how long it takes to encounter a conservative or libertarian speaker. Or try searching for speakers like Arthur Schlesinger and Milton Friedman, Julian Simon and Lester Brown, and see what results turn up. Or check out the 10-part series on same-sex marriage, which appears to be tilted 8 to 2 in favor. Which is OK with me, as that’s also my position, but it might not quite reflect the viewpoints of the diverse taxpayers who are paying for the service.

But one might say, so what if NPR and PBS tilt to the left? Lots of media have an ideological slant. You’re not likely to see Bernie Sanders on Fox, and Rand Paul has probably learned what kind of reception he’ll get at MSNBC.

The difference is that NPR and PBS are funded by taxpayers (not entirely, but to the tune of hundreds of millions of dollars a year). The First Amendment protects freedom of speech and of the press. But no one has a right to government funding of his or her speech. And when government does speak or fund speakers, the legal rules become far more complex than when a private person speaks. Surely the taxpayers and their representatives have some say over what they will pay for, and that means that recipients of government funding are constantly looking over their shoulder to see if they’re offending their patrons in Congress.

Somepeople on the left have advocated that public broadcasters liberate themselves from taxpayer funding so they could become more aggressive. It’s quite possible that an NPR free of taxpayer funds and political strings would be more vigorously liberal than it is now. That’s fine. Under the First Amendment, independent media have the right to be as liberal, conservative, libertarian, socialist, national socialist, bigoted, or religious as they want. Just don’t make the taxpayers pay for it.